This invention relates to improvements in extruded construction for bags, and is more particularly concerned with a construction especially suitable for reclosable bags which are adapted to be initially hermetically sealed and which after being opened are reclosable.
A wide variety of products from foodstuffs to hardware and materials in liquid or granular form are desirably packaged in flexible plastic bags which may or may not be transparent or at least translucent. With certain types of packaged contents, it is desirable to provide means preventing unauthorized access to the contents or to prevent spillage. Often the contents must remain hermetically sealed until used. With pourable contents, whether liquid or particulate. It is often desirable to have the bags equipped with pouring spout means. A type of bag which is especially suitable for these purposes is disclosed in U.S. Pat. No. 3,746,215. However, the bags disclosed therein are constructed from a plurality of separately formed parts secured together in a manner that complicates and increases cost of manufacture because of the particular multi-part fabrication and the necessary assembling and securing together of such parts. In particular in that patent the gusset member is formed as a separate piece or pieces and then heat sealed to the inner surface of the main container inwardly relative to the separable fastener profiles. That construction is difficult and expensive to make.
A principal aim of the present invention is to provide a new and improved construction in which the closure web or gusset, pull flanges and separable fasteners, at least, are all part of an integral one piece extrusion to which the side wall panels of the bag body may be secured or may be connected as an integral part of the extrusion.
Tubular extrusions for manufacture of bags are disclosed, for example, in U.S. Pat. Nos. Re. 29,331, Re. 26,991 and 3,380,481. Although those patents disclose the integral extrusion of film and of separable zipper type resiliently flexible fasteners, they fail to have any provision for a flexible closure web area inwardly from the flexible fastener profiles with pull flanges extending outwardly relative to the fastener profiles, the closure web area being adapted to serve, if desired, as sealing gusset means which may also provide pouring spout means.